The present invention relates to an ATM (asynchronous transfer mode) cell assembling/disassembling system and, more particularly, to a system for managing and controlling an address table used to determine transmission address information when assembling and disassembling ATM cells.
In a CLAD (cell assembling/disassembling) unit for disassembling and reassembling VBR (variable bit rate) system data, for instance packets, received from a LAN (local area network) such as ETHERNET, into and from ATM cells, an address table for registering address information is provided. The address information included in the received ATM cells such as a transmission source address SA indicative of the transmission source, VPI (virtual path identifier) for identifying different virtual path links that are multiplexed in the same physical layer connection on an ATM layer and VCI (virtual channel identifier) for identifying different virtual channel links in the virtual path connection are registered.
When disassembling the received packet data from the LAN to generate an ATM cell, the address table is retrieved by using a destination address DA of the received packet data as a retrieval key, and the ATM cell is generated on the basis of the retrieved VPI and VCI.
In this prior art address table management and control system, when registering the transmission source address SA, VPI and VCI included in the received ATM cell message in the address table, the address table is retrieved. If these data have not yet been registered, they are additionally registered in the address table. If they have been registered, the registered contents are updated.
In such prior art address table management and control system for determining addresses, the address table is retrieved for each received message by using ATM cells, increasing the retrieval time and adding considerable overhead to the process of address determination.